If there's a lot of people early, they won't magically disappear at 1pm. All that will happen is your wait starts then verses being over by then.
It's like going to the DMV. You know it's a 1,2,3,4 hour or whatever affair no matter what. Sure, you tell yourself it's better at X time verses Y time, but is it really?
As a counter argument, I think 1pm is worse. All those who pre-ordered but are on the fence (money, not sure, whatever), will realize they have 2 hours to get it or lose it and thus rush to the store as a last minute impulse purchase. Could be worse than the morning.
And in the morning workers are fresh and things more brisk. By afternoon it's just dragging on.
Either way, enjoy your new iPad. 🙂